- Calendar items that are created on the mobile device are missing from the Exchange Online mailbox.
- Calendar items that are created in the Exchange Online mailbox are missing from the mobile device.
- Remove the ActiveSync relationship on the mobile device.
- Remove the ActiveSync relationship from Outlook Web App. To do this, follow these steps:
- Sign in to Outlook Web App.
- Click Settings ( ), and then click Options.
- In the left navigation pane, click Phone, and then click Mobile Phones or Mobile Devices.
- In the list, select the ActiveSync relationship, and then click Delete.
- Disable any Outlook add-ins that are used to set up calendar items. This includes add-ins that are used to set up conference rooms.
Note The Outlook add-ins can be re-enabled after the issue is resolved.
- Restart the mobile device.
- Re-create the ActiveSync relationship on the device, and then confirm that the issue is fixed.
- A corrupted ActiveSync relationship
- Third-party Outlook add-ins that change the calendar items
Article ID: 2293282 - Last Review: Dec 16, 2016 - Revision: 1